Selector rack for automatic telephone systems



Oct. 9, 1923. v 1,470,202

A. E. STEVENS SELECTOR RACK lfOR AUTOMATIC TELEPHONE SYSTEMS Filed Aug. 2, 192.1,

Patented Oct. 9, 1923.

ALTON E. STEVENS, OF PROVIDENCE, RHODE ISLAND.

SELECTOR RACK FOR AUTOMATIC TELEPHONE SYSTEMS.

Application filed August 2, 1921.

To w ll /1 n m it may concern Be it known that. I, ALToN E. STEVENS, citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Selector Racks for ,.:\.uton1atie Telephone Systems, of which the following is a specification, reference being bad therein to the accompanying drawings.

My invention relates particularly to racks used in the central switchboards of private telephone systems, for supporting the selec tor mechanism, and has for its object, the simplification of the construction of such racks. and the facilitation of their n1anufacture.

In the drawings illustrating the principle of my invention, and the best mode now known to me of embodying the same in operative striuture:

Fig. 1 is a plan of a bracket integral with a backboard, not shown.

Fig. 2 a plan of the top of jack end of the selector rack;

Fig. 3 a plan of the rack with top piece removed;

.Fig. 4 a front elevation bracket;

Fig. 5 a side elevation of the rack, bracket and back-board;

Fig. 6 a simplified diagram of the circuits of an automatic telephone system employing these racks.

Referring to Figs. 1, 2, 3 and 4, to a baclr board 1, Fig. 5, are permanently secured a. bracket 2, and two posts 3. The bracket 2, Fig. 1, is slotted at 4, and has secured to its upper surface by eyelets 6, a sheet of insulating material 7. carrying a number of jack springs, as 8 arranged radially to conform to the radius of the slot 4. and staggered as shown. The jack springs 8 are secured by eyelets 9. Figs. 1 and 4t. 1

The selector rack is removably secured to the bracket 2, and back-board 1. and consists of two angle irons 1.0 held at the bottom by a strap 11, Figs. 4 and 5, which is riveted to the angles, and a top piece .12, Figs. 2 and 41, also riveted to the angles. On the face of the angles are pairs of pins 13 arranged one pair above another. each pair to receive a selector 14, Figs. 3. 4. and 5, the selectors thus being arranged in a vertical series, and each selector being secured by screws 15 in. pins of the rack, and

Serial No. 489,289.

13; the selector frames having holes to slide over the pins.

Ad acent to each pair of pins and secured to the angles, is a horizontal metal arch 16,

Figs. 3, 41 and 5, caii'rying a'segment of insulating material 17, each segment having a series of holes 18 for the reception of vertacting the metal.

Secured to the to piece 12 by rivets as 22, is a segment 23 of insulating material, having holes 24 corresponding in position with the holes 18, in segments 17.

A. second segment of insulating material 25, Figs. 2 and 4., of the same shape as 23, is also secured to the top piece 12 by the same rivets 22, as is the first segment 23; the said rivets 22 having a shoulder whereby the two segments are held a distance apart corresponding to the diameter of the contact busbars 19. The second segment 25 has holes as 26, these holes being staggered and positioned the same as the jacks 8 in the piece 7, of the bracket 2.

The contact bus-bars 19, see Fig. 4, are given a bayonet bend near their upper end; that is, two right angle bends as illustrated. When these contacts bus-bars 19 are assembled in the rack, one for each hole as 18 in segments 17, the rods extend vertically from the top segment 28 through the entire series of segments as 17, to the bottom of the rack, the bent ends of the busbars 19 be ing staggered, so that the short vertical ends extend, through the holes as 26 in segment 25, these short ends forming plugs which engage and. contact the jack springs 8, when the plugs are pushed up through the eyelets 9 which secure the springs 8 to the piece 7.

The parts of the selector rack are assembled as follows: The pins 13, see Figs. 4 and. 5. are staked into the angles 10; the top piece 12and the strap 11 are then riveted on, thus holding the rack together; next the arches 16, carrying the segments 17 are riveted to an angle at each end, and lugs 27. designed to support a line terminal board 28, are staked into the lett hand angle. Next, the segment 23 is riveted to top piece 12, and a contact bus-bar 19 run down through each of the holes in each of the segments the bent ends being above this piece 2-1). and staggered so that the segment 25 may be pushed down over them and riveted into place on the upper end of rivets 22.

The horizontal bends in the contact bus bars 19. between the two segments 23, lock the said bus-bars 19 against longitudinal movement, which are thus held tor their entire length in insulating material, and have their upper ends so positioned, that each will enter an eyelet hole as 9 in piece 7, and contact a jack spring as the said jack springs having a tag 102, to which wires may be soldered to connect them to corresponding springs on other rack brackets. A line terminal board 28, Figs. 4. and 5. of insulating material is secure to the lugs 27.

A battery jack has one member 29, Fig. 1. secured to bracket 2 and carries two contactjacks 30, 31; while a second member 31', ecured to top piece 12, carries two jack plugs 33 and 8%. designed to engage the contact jacks 39, 31. when the rack is inserted in place in relation to the bracket 2. The jacks are shown in circuit. in Fig. (3.

ikdjtufttllt to each selector position. on the line terminal board 28, are three springjacks as 37. 38 and 39, Figs. 5 and (5; and in eacl selector frame as it, are three jack plugs +10, 41 and :2. in an insulating block t3, Fig.

l. and designed to contact jacks 37, 2-38, and 35, when a selector is installed on the pins t3.

The line terminal board also carries three connectors for the lines assigned to each selector, as at 13, t4.- and t5, Figs. t and (3.

To install the selector rack in the bracket 2, on the back-board i, the pins 36. on the sides of the rack are moved up into the slots 35, Fig. in the bracket, thereby causing the plug ends of the contact bus-bars 19, to register correctly with the eyelets 9 in the jack springs 8, Figs. 1 and at: the jack plugs 33 and 3% in the top piece 1:2 engaging the contact jacks 30, 31 of the battery jack secured to the bracket The rack is retained in position by two screws 50. through holes 51, screwed into posts 3.

Each selector. as 14., Figs. i and 5, is secured on pins 13 by screws 15. and carries an arm 47, on which is mounted a spring contact shoe lS, the arm 1? being secured to shaft 20 and ratchet wheel t9 but insulated trom them. As the shaft 20 is caused to rotate. the arm 2 :7 turns with it, and causes shoe 1-8 to successively contact the contact bus-bars 19. The teeth in the ratchet wheel 19 are spaced corresponding to the spacing oi the contact bus-bars 19, so that each step of the ratchet wheel, advances the contact shoe to the next succeeding mtact bus-bar.

A brush 51 maintains electric *ontact with the arm 17 during the latter's rotation. tor circuit reasons, in a well known manner.

Complete selector mechanism has not been shown in Fig 3. st, as this forms no part of the present invention, but tor the purpose of explanation, it has been illustrated diagrammatically in Fig. (i.

As there may be several racks in each system, and the contact bus-bars in the same positions in each rack are connected to the same telephone station line, each jack spring as 52, Fig. l, on the first bracket. is con nected to a correspoinling jack spring as 53, 54, on other brackets in a system by a wire as 55. 56, these wires being laced together in the form or a multiple cable, as in common practice.

I will now describe the operation ot a simple automatic telephone system in conneo tion with my invention. Reterring to Fig. 6, A represents the circuits and apparatus of a calling telephone station, and B the selector mechanism. C represents the circuits and apparatus of :1 called telephone station, and D the selector mechanism of same.

A wishes to call C. The receiver 57 is lifted, causing book 58 to break from Fat and bringing contacts 60, (it together. there by completing a holding circuittrom positive. side 64: of battery (35, through jack 30, wire 66, connector 45, contacts 60. (31, primary G9, transmitter 70, wires 71, T2, connector 4E3, jack 3?, connecting magnet '73, jack 38, wire 64:, jack 31 to negative side (59' of battery 65; connecting magnet- T3 is thereby energized and attracts armature H, which causes spring detcnt T5 to engage ratchet wheel 49, and retain it in each successive step to which it may be moved. Armature 71- has comparatively weak adjustment, while armature T5 is adjusted stillly, and is not attracted on account of the resistance of primary 69 and transmitter 70, in the circuit.

Stepping key 62 is now pressed into contact with (33 tour times, this being the call number of station 0. A stepping circuit is thereby completed four times, from positive side (34- oi battery 65, through jack 30, wire (36, connector contacts (50, 61, (3 key 62, connector 4-1-1, jack 39, stepping magnet 67, jack 38, wire (3%, jack 31.. to negative side 69 of battery (35. Stepping magnet 67 is energized four times. attracting armature 68, and causing pawl T6 to engage, ratchet 49, and step it around four teeth, thus bringing the shoe s8 into contact with contact busbar 77, upon which it will come to rest.

Ringing key 78 is now pressed into contact with T9 and completes a connecting and Inc ringing circuit, by short circuiting the primary 69 and transmitter 70; the el11n1nation of this resistance causing enough cur rent to flow through magnet 73 to attract connecting armature 75, which causes contact between springs 80, 81, and completes a ringing circuit as follows :-from positive side 64 of battery 65, through jack 30, wire 66, connector 45, contacts 60, 61, 79, key 78, wires 71, 72, connector 43, jack 37, springs 80, 81, brush 51, arm 47, shoe 48, contact bus-bar 77, Wires 78, 82, connector 83, ringer 84, contacts 85, 86, connector 87, jack 88, magnet 89, jack 90, wires 91, 64, jack 31, to negative side 69 of battery 65. The ringer 84 is therefore operated, and signals the party at station C.

The ringer 84 is of high resistance and the magnet 89 is of low resistance, and does not attract its armature which is stiffly adjusted, strongly enough to operate same.

The armature 75 is so adjusted, in a manner well known, that after it pulls up against the end of magnet 73, it sticks there after the key 78 is released, and the resistance of 69 and 70 re-introduced.

The called party at station C now removes receiver 92 from hook 86, causing 93 to contact 94, and the parties at the two stations may now converse, the transmitter at each station being energized over their holding circuits as before described.

The talking circuit is as follows:from common wire 95, through connector 45, contacts 60, 61, primary 69, transmitter 7 0, wires 71, 72, connector 43, jack 37, springs 80, 81, brush 51, arm 47, shoe 48, bus-bar 77, wires 78, 82, connector 83, transmitter 96, primary 97, contacts 94, 93, connector 98, back to common Wire 95. Transmitters A and C are each energized over individual battery circuits, the energizing circuit of A being as follows :from positive side 64 of battery 65, through 30, 66, 45, 60, 61, 69, 70, 71, 72. 43. 37. impedance 73, wire 64 to neg ative side 69' of battery 65. The energizing circuit of station C may be traced in a like manner.

Fluctuations of current through the primaries 69, 97, caused by transmitters 70, 96, are repeated by induction in secondaries 99, 100, and affect the receivers 57, 92, in a well known manner, and conversation can be car ried. on.

When the receiver 57 is replaced on hook 58, the member breaks contact with 61, thereby interrupting the holding circuit and causing the magnet 73 to become de-energized, the armature 74 returning to normal position, and causing detent 75 to release ratchet wheel 49, permitting the latter, and the arm 47 and shoe 48, to return to normal position by treason of a suitable: spring, shown at 101, Fig. 4.

llfaving now described the features and operation of my invention, and desiring to protect the same in the broadest manner legally possible,

lVhat I claim is 1-- l. A vertical rack; horizontal insulatin spacers, one above another; fixed vertica contact bus-bars retained in their relative positions by said spacers; selectors for said. rack; and means whereby said selectors may successively engage said bus-bars.

2. A vertical rack; horizontal insulating spacers, one above another; vertical contact bus bars retained in their relative positions by said. spacers; pins perpendicular to the face of the said rack; one or more selector frames with holes therein to allow a selector to be removably mounted upon said pins; the said contact bus-bars being each engageable by the wiper of said selector.

3. A vertical rack; horizontal insulating spacers, one above another; vertical contact bus-bars retained in their relative positions by said spacers; pins perpendicular to the face of the rack; one or more selector frames with holes therein to allow a selector to be removably mounted on said pins; the said contact bus-bars being each engageable by the wiper of said selector; jacks secured to said rack whereby the selector circuits become connected, or disconnected when the selector is mounted on, 01' demounted from the selector rack.

4. A vertical rack; horizontal insulating spacers, one above another; vertical contact bus-bars retained in their relative positions by said spacers; pins perpendicular to the face of said rack for the-purpose of receiv ing and positioning selectors; a terminal board secured to the said rack and having terminals therein horizontally adjacent to each selector position.

5. A vertical rack; horizontal insulating spacers, one above another; vertical contact bus-bars retained in their relative positions by said spacers; pins perpendicular to the face of the rack; one or more selectors with frames having holes therein whereby they may be reinova-bly mounted on said pins, the said contact bus-bars being engageable by the wiper of said one or more selectors; a terminal board secured to the rack and having terminals and jacks horizontally adjacent to each selector position; a plug jack for each selector whereby the selector circuits may become connected or disconnected when the selector is mounted on or demounted from said rack.

6. A vertical selector rack; horizontal insulating spacers, one above another; vertical contact bus-bars held in their relative positions by said spacers; a back board carrying a series of jacks and means whereby said bus-bars may engage said jacks.

7. A vertical selector rack; vertical contact bus-bars arranged radially around a common centre. each having a free end: lnn'izoinal insnlatine' snaews to r tain said h i a hack hoard carrying a series of jacks; and means d ha l: hoard, the free ends (Ci: Mu of said has-liars engaging the said jacks.

i). A vertical selector rarlt: X'QItlCtitl eon-- :aet hns-l ars. each haring a herzt free end, the hends heing arranged alternatively in opposite directions, or *ae 'eredg a series f jacks suitably Inonntec to receive the hent free ends oi" said hnshars; selectors l'or said ra l1; and means whereby said selectors nia successively engage said bushars.

it). A i'iXed \erti #al selector rack; vertical eoniact has-bars each having; a free end: a eries oi iaclqs suitably mounted; and means whereby the tree ends ot' said hnslnn's encare said jacks; selectors for said ac-l1; and 111 21118 whereby said selectors may sneeessively engage said bus-liars.

ll. Two or more series of jacks; a suitahle mounting for same; a multiple cable whereby each iacl; in eaeh ser neatly connect: to a correspini an l other series; a plnral t of each having a Vertical series ies ack in selector of con; mL's-bars er aving; said jacks, snitahly n nit held in insalznii r-rial antl aranged radially adjaee ilector positions; pins at each selector position perpendicular to the lace ol ll said rack; a so-- ric:- ofja' 'slnn'izontallrad acent to each selector postion; selectors hating f nines with holes therein whereby the may he 1G1HO\'- ahi niinniled on said pins, EiM'll selector haring or engaging the said rs; and each selector having a lies to engage the said jacks adjacent to itself.

A vertical selector ract; vertical eon :ns-hars snitalalv held in insulating roaand arranged in radial relation to a series ol" selector positions; pins at eaeh seleztor position per-pendicnlar to face of said rack; a terminal board secured to said rack and having! a series of jacks and a series at terminals horizontally adjacent to each selector position; select 'n's, each hating a frame with holes \vherel'rv it may he renm'ahly mounted on said pins; each selector having a series of plugs to 011;: ge the said jacks; and each selector having a rotatable co tact w n her for engaging said bus-bars.

in testimony whereo'l l. hereunto allix my signature.

ALTON E. STEVENS. 

